What size beam do I need?

[BioSphere]

I have been out of the hobby for 10 years. I am planning on a 300 gallon in wall tank build with a fish room in the rear. I want to change the stand I have so that there are no center supports on one side on the stand. (I bought a used tank and stand-so I have to adapt) I need better access to my sump which will be below the stand. The question is whether the microlams running the length of the tank are strong enough without the center supports on one side of the stand? The tank size is 96" x 30" x 24". The microlam is 6.5" x 2.25" x 98". I was thinking of bolting one 2x6 or a 2x8 to the stand side without the center supports. I could not bolt 2 boards because of the house mechanicals that share the room. I do not want to bolt a wider board because it will hang too low, making it harder to reach "stuff" in the sump. I suppose that I could bolt a 2x10 or 2x12 and align the bottom of the 2x10 or 2x12 with the bottom of the microlam. The tank would not be resting on top of the bolted on piece of wood. Any suggestions would be much appreciated!